contagion
nounLiterally, a touch or touching. Hence, the communication of a disease by contact, or the matter communicated. More generally, that subtil matter which proceeds from a diseased person or body, and communicates the disease to another person; as in cases of small pox, measles, anginas, and malignant fevers; diseases which are communicated without contact. This contagion proceeds from the breath of the diseased, from the perspiration of other excretions.